Hitherto, optical disc apparatuses that are configured to record information on circular-plate-shaped optical discs, such as CDs (Compact Discs), DVDs (Digital Versatile Discs) or Blu-ray Discs (registered trademark, hereinafter referred to as BDs) and configured to read such information from such an optical disc have become widely popular.
In such optical disc apparatuses, various kinds of information, such as various content, for example, music content and video content, or various data, for use in a computer, is recorded on an optical disc.
In particular, in recent years, the amount of information has increased due to video having a higher definition and music having a higher sound quality, and also, there has been a demand for more content to be recorded on one optical disc. Therefore, there has been a demand for such optical discs to have a larger capacity.
Accordingly, as one of techniques of enabling such optical discs to have a larger capacity, a technique has been proposed in which a two-photon absorbing reaction is used to form recording pits indicating information, and such recording pits are arranged in a three-dimensional manner (see, for example, Patent Literature 1).
Patent Literature
PTL 1: Japanese Unexamined Patent Application Publication No. 2005-37658
PTL 2: Japanese Unexamined Patent Application Publication No. 2008-71433
Non Patent Literature
NPL 1: A. Toriumi and S. Kawata, Opt. Lett/Vol. 23, No. 24, 1998, 1924-1926